DHT-Walnut

please note this page is in updating, it has been merging from the old version of wiky, so keep patient, i will rewrite this documentation in pretty as soon as possible

in case you need a pdf copy of the old doc, or if you need attachments feel free to ask me for them ( speeder@alice.it )

DHT-Walnut is a shortened name for the Digital Home Technologies PCB 01070201 Rev. 1.1. The DHT-Walnut board is based on the AMCC-Walnut (still available, and still expensive :P). It is a more improved board described at www.amcc.com. A "walnut" searching will inform about schematic and software. Also keep attention @ DENX: they have developed a lot for the AMCC-Walnut board, and you could find a linux patch for your problem, prettier documentation, developer suit, and much more: in case, you are suggested to have a look to their web pages.

Well, the board consists of:

* [:PPC405GP:PowerPC 405GP] running at 266mhz
* PC133 SDRAM slot, currently, only supports single sidded DIMMs
* On-chip 405GP ethernet, board doesn't have an ethernet MAC address (the monitor/bootloader is able to fix it)
* DCE serial port, speeds up to 230k, only tested to 115200bps
* two pci slots, keyed for 5V only cards
* Promise Technologies ["PDC20265"] IDE
* 512k of boot flash AMD 29LV040B [attachment:amd29lv040b.pdf datasheet]
* it is soldered on the PCB
* if you like to use a socket you have to consider the bootloader will check for the flash manufactor ID, so or you replace the 29LV040B with an other socked-29LV040B, or you have to modify the bootloader
* 12v dc powered
* 2A max
* it is able to feed the hard disk
* 6.00" x 7.5" board size

The system's most common configuration seems to be:

* System PCB
* no RTC (the real time clock chip is missing)
* 32M PC133 SDRAM DIMM
* the board has issues with more than 128M: if you inspect the pcb, you will see that the DIMM connector has same pin missing, this is the reason why you can't use DIMM bigger than 128M
* PCI IEEE-1394 card supported by OHCI driver
* PCI additional ethernet board
* needed cause the on board ethernet is implemented by the IBM-ppc-405GP, for example netbsd is not able to drive it, so in case you need an additional board, the one provided with DHT is good enough
* PPCBoot v.1.1.2 in flash (it has issues with environment, it need to be replaced with a gooder one)

JTAG & OCD Commander

The OCD Commander is macraigor's free debugger software, which allows you to connect to your supported target type chip via the On-Chip Debug port (BDM or JTAG) using a Macraigor hardware device. You will be able to test the connection, memory access, modify memory and registers, run code and more using this product. This debugger is not designed to be used to program flash devices connected to your target.

* OCD Commander macro file to configure the system for recovery attachment:recovery_config.mac
* CPU configuration of the system after a warm reset attachment:warm_reset.config
* CPU configuration of the system once ppcboot v1.1.2 is up and running attachment:ppcboot.config
* CPU configuration of the system once ppcboot v1.1.6 is up and running attachment:ppcboot_116.config
* Example OCD logfile of the using the recovery macro to load ppcboot attachment:ocd_recovery_log.txt
* Example console log from ppcboot v.1.1.6 running from ram after recovery macro attachment:ocd_recovery_console_log.txt

Bootloaders

* ppcboot
* Here is the latest ppcboot 1.1.6 patch, as is, it will build for flashing at 0xfff80000 as a replacement for the pcboot-1.1.2 that comes with the board.
* attachment:patch-ppcboot-1.1.6-km2 Original sources for ppcboot: ftp://ftp.denx.de/pub/ppcboot/ppcboot-1.1.6.tar.bz2
* Here is a binary for those without a toolchain. attachment:ppcboot1.1.6.1.bin crc = 083fb0a3
* S-Record attachment:ken_ppcboot.srec
* use this (at your own risk) see the detailed update procedure description: [:DHT-WalnutInstallingTheUpdatedBootloader:Installing the Updated Bootloader]
* U-Boot
* It is a significantly updated replacement for ppcboot.
* [:DHT-Walnut-U-Boot:U-Boot for the DHT-Walnut]
* DENX U-Boot and Linux Guide for Walnut

Userland

* [:DHT-Walnut-DebianInstall:Debian GNU/Linux netboot installer] -- Install Debian from the internet to a hard disk.
* Netbsd has a port for "IBM PowerPC 405GP based Walnut evaluation board", this is not the DHT-Walnut, this is an other way to call the AMCC-Walnut (yes just to be confusing). Ok, it is not for DHT-Walnut, but this port could be (easealy / hardly) adapted to the DHT-Walnut with some work / over work.

Hardware that is known to work with Linux

There is a list of the Hardware that is known to work (and not to work) with this board.

Linux has a problem in the source's tree: the Walnut has been originally ported to arch=ppc, while the new kernel tree is around arch=powerpcc, for this reason you need to specify the right arch or your compiler will have issues. Developers will port everything to arch=powerppc in the future. Kernel 2.6.12 is free of this problem, newer than .12 have it.

How-To's

* How To [:DHT-WalnutInstallingTheUpdatedBootloader:replace the bootloader with ppcboot 1.1.6]
* How To [:DHT-Walnut-U-Boot:replace the bootloader with U-boot 1.1.4]
* How To [:DHT-WalnutJtagBootloaderInstallation:recover from "Brickage"]
* How To [:DHT-WalnutBootViaTftp:boot via tftp]
* How To [:DHT-WalnutBootingFromHdd:boot from Hard Disk]
* How To [:DHT-WalnutGPIO:control the Green Media LED and J5]
* How To [:DHT-WalnutUsefullProjects:do something useful with your board]
* More to come...

People you could contact if you need help

* people on irc freenode #edev #mklinux may be asked about
* ddc (i'm currently use this board for an university project running gentoo-ppc)
* msn daredevil-coder@hotmail.com
* email mr.ddc@alice.it
* you ... if you want ;-)

A binary that can be copied to the DHT-Walnut flash at 0xfffc0000 is available here: u-boot-1.1.4-df2.bin

Changes since u-boot-1.1.4-df1.bin:

* A default ethaddr is now set: de:ad:be:ef:00:00
* The ethaddr can be changed as often as you like. Use: setenv ethaddr be:ef:be:ef:be:ef ; saveenv
* Only the first two memory banks of a DIMM are used. This allows us to use (half of) double-sided
DIMMS.

Recovering a bricked DHT Walnut board

Using OCD Commander, a JTAG adapter, and GPSFan's ram resident ppcboot, it is possible to reprogram the flash. In short, use OCD Commander to turn on the sdram, download the ram targeted ppcboot, and install a new bootloader.

There's also an experimental ram-resident version of u-boot-1.1.4 attachment:u-boot-ram.s19 that can be downloaded to 0x400000. Source diffs against the current version from CVS, incorporating the patches from both GPSFan and dfarnsworth: attachment:u-boot-ram.patch . Expect to see much more output at boot, as this version has debug output turned on. (Other changes include setting the entry point in the linker script, output files renamed to u-boot.s19 and u-boot.elf, sdram config disabled, added debug info on code relocation, and a modified default environment.)

At this point, you should have a running ppcboot v1.1.6. Install a new flash resident bootloader using the bootloader update procedure [:DHT-WalnutInstallingTheUpdatedBootloader:Installing the Updated Bootloader]

page was renamed from AddJ10

suck or wick the solder out of the holes and solder it in, but be minded a common header has pins larger than holes, so ... be careful about what you do: you could damage the PCB

(2) in case your lab is equipped with the bdi2000, you are warned this hw is known to be working with the dht-walnut jtag. In case you are not equipped with, you are warned this hardware is expensive a lot, 'cause it is not a simple download cable, it a professional debugger)

DHT-Walnut as N.A.S.

attachment:wal-mini.jpg

I turned a DHT-Walnut + 300Gb hard disk into a file server to have my data files connected and shared to the LAN (Local Area Network).

N.A.S. stands for Network Attached Storage. They are storage devices attached to the lan. A NAS should be able to be connected to every kind of network. It should use both the access protocols NFS (Network File System) and CIFS (Common Internet File System)

I only enabled NFS service in the kernel configure because i don't need CIFS. UNIX servers use NFS, while Microsoft systems use CIFS, fortunately i don't have any Microsoft systems here :P Gentoo is installed in the first little partition of the hard disk (it is PC-partition style, so you can only have 4 partitions). It runs openssh, telnet, ftp, tftp, and NFS. As the fact there is no RTC chip installed i added special /etc/init.d/clock-sync to set the local time. The scrips uses rdata to retrieve the current time of an other machine.

In the photo you could see the case i realized: the hard drive is connected to the opened door, the DHT-walnut PCD has been placed inside, the green LED has been used to the frontal case to say "the booting has been completed, the system is ready" (used the gpio hack provided in patches for the 2.6.16-rc3). The black platform is from sony playstation2 and is is only a nice way to have the case vertically seated.

Don't keep about the ALS4000 pci sound board plugged in the upper PCI bus. It has been plugged just to use the NAS as the giant (300Gb) ipod you have ever seen .... but this is an other story ....

DHT-Walnut as MP3-player

Following in the footsteps of Nate True, I turned a DHT-Walnut + parts into a server to play my music collection. It grabs the data via nfs from an NSLU2, and is controlled via various mpc-like clients from my desktops.

After the above was running flawlessly for a day, somehow the usb audio device got fried. May have been a ground loop in the stereo. I had gotten used to having music playing. so I dug out an old PCI sound card (CS4280 based) and compiled the drivers and plugged it in. GIGO... seems like IBM4xx DMA support needs to be turned on in the kernel to make it work. Things are fine now with a few extra ground wires, just to be sure.

Note: to use a PCI-sound card you need to use ppcboot. U-boot-1.1.6 has an issue with kernel initialization. It is under fixing, but today it causes the DMA not to work correctly with the sound card. No sound at all.